mirousse

Don't worry..this idea is out the window for me. My brand new VW jetta burned down to ashes after 10k a few years back...assembly problem...! I was driving the car when it cought on on fire... since then fuel and I keep the common relationship to a minimum...gas station meeting only!

robot808

That's just not right Mike.

jcorenman

Having recently had one of these suckers apart, there is no reason a pump in good condition should make more noise than the usual quiet buzz. It's a vane-type pump, with little rollers that fit into slots in a rotor and move in and out as the rotor spins inside the housing. Nothing in there that should be making much noise.

What I suspect is that the rollers get out-of-round with wear, and/or the slots get worn and the rollers start catching or rattling. Think of it as a fuel-pump rod-knock-- still runs, but for how long? If the budget allows and/or you are adverse to getting stuck, then I would suggest changing it.

Cooler temps and Stan's mystery oil will certainly help short-term. The reverse-polarity trick might also be worth a try, but take the pump out and use Marvel Mystery oil to flush it instead of fuel. (Fill it with oil before applying power, the brushes run in fuel and I wouldn't want to power it up with just fuel vapor in the pump).

the flyin' scotsman

We had very warm temps in Sept that fell to -20C over thanksgiving and have rebounded to approx 5-9C. A skiff of snow which makes tracking the hunt interesting. Its that time of year where we can't risk taking the 928 out overnight............the snow faries may arrive anytime soon

In regard to the FP I'm of the mind set to replace especially if the age is unknown or is original.

Landseer

I've had a new one buzz for a day, then jam.
Following Jim's procedure would be the way to go.

You can put hoses over each jaw on vicegrip longnose pliers and use them to pinch the hose that links gas tank with fuel pump inlet. Then remove pump.

Mrmerlin

Malcolm actually the fuel will get rather warm as it is being pumped to the fuel rails and then the extra heated fuel goes back into the tank.
Just because the OAT is cooler doesnt mean the fuel will be, this situation get worse as the fuel level drops in the tank.

Like i have also mentioned a pump may get louder if the car is run for a longer period of time and the fuel level is less than 1/2 tank. Hotter fuel will make the pump noise increase
Since the OP also said that the pump noise returned to normal once the car cooled off this tends to confirm my original statement

mirousse

Again the symptoms are in line with Mrmerlin. Tank level was at 1/4. I can afford to change it but I would rather do it when the car comes back from winter storage at spring and drive it as much as possible during the few snowless remaining days. I wanted some advices to evaluate how high is the risk of having a pump failure before the winter storage.

Malcolm, snow forcast is pretty accurate a few days in advance on the eastern side. Driving the 928 is not even a risk. Here poeple tend to store their summer car in october not for weather reasons, but to avoid paying an extra month of license registration.

Thank you all for your precious inputs...again!

Michel.

the flyin' scotsman

Valid points Stan but the OAT is well below freezing.

My FP has exactly the same symptoms as Michel so will try the 'add more fuel' solution when it buzzes again...............should be about June/July '10

Michel...........enjoy the last few days of the season; I have a major trip this weekend +1k kms but will have to leave the 928 home, weather is to unpredictable.

Mrmerlin

didnt know about the OAT being below freezing ,thanks for the input Malcolm, I would think that the OAT being that cold could also reduce the fuel temps it will still be getting some heat from the engine though.
Best to add some MMoil and keep more fuel in the tank, good luck whatever you choose.
Also if your worried about a pump failing just order the new pump and put it in the glovebox till the one you have now fails

tailpipe

My pump in the red 79 euro buzzes when I use cheap gas. try putting some good gas in it and see what it does.

SwayBar

All my 928's, their fuel pumps have buzzed on and off randomly with not one failure; I would not worry about it.